For the first 40 hours, you get paid $7 per hour: 40×$7 = $280
For the next 5 hours, you get paid 1.5×$7 per hour: 5×1.5×$7 = $52.50
Your total pay for 45 hours is $280.00 +52.50 = $332.50
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Note that the 5×(1.5×$7) can also be considered to be (5×1.5)×$7, which is to say, pay at the normal rate for half again as many hours as were worked. That means, you could compute the pay as 47.5 hours times $7 per hour = $332.50.